This invention relates to digital communication systems and in particular to a technique for automatically configuring system components.
The past decade has seen a tremendous expansion in the deployment of network computing technologies. As organizations have realized cost benefits and productivity gains through their widespread use, they began expanding existing networks almost as rapidly as new products became available. In the past several years, growing pains from this expansion have continued to be felt, especially by those who have deployed different and sometimes incompatible technologies and products.
The typical computer network includes several different types of internetwork elements that permit an end node or user node, such as a personal computer (PC), to be connected to other computer equipment, such as a host computer or service provider. The network typically also may include a sophisticated suite of internetworking devices such as stand alone routers, router modules for shared-media hubs, switches, file servers, multi service wide area network (WAN) access switches, asynchronous transfer mode (ATM) capable multiplexers, and other devices.
The primary problems associated with network expansion include day-to-day network operation management, as well as strategic network growth planning. Specifically, each new network technology typically requires its own set of experts to operate and maintain. Staffing requirements for managing large networks created a crisis resulting in the development of automated network management tools that may be integrated across diverse environments.
One such automated management tool which has enjoyed success is the Internetwork Operating System (IOS(trademark)) software available from Cisco Systems of San Jose, Calif. Cisco""s IOS software is a unifying thread that connects otherwise disparate hardware, providing security, reliability, and investment protection in the face of network growth, change and new applications. IOS is a remote process protocol using messages in the UDP/IP format.
Ideally, the appropriate components of the IOS software are installed in each internetwork device to create a single, unified infrastructure to manage resources and thereby distribute the network intelligence.
The management services provided by an operating system such as IOS provide such features as:
setting up and configuring of networking devices to monitor activity and to administrate enabling network services for multicast, multimedia, and other applications;
performing optimization functions for bandwidth management, load sharing over multiple links, and congestion control; and
troubleshooting to find and resolve problems quickly through automated alarms and other methods.
IOS software thus provides the management services capabilities to control the network on all levels, from physical port configuration to advanced application support.
Even with the adaptation of IOS software or its equivalent, however, network configuration is still an issue. For example, the fewer the number of operator controlled steps needed to configure a particular network device, the easier the job of system administration is. However, each internetwork device must still typically be at least subjected to some initial setup procedure.
For example, internetwork devices such as routers, switches, multiplexers, hubs, bridges, and the like typically provide a separate interface such as an Ethernet type connection, to permit them to communicate with management level services. This communication path is typically separate from the path for the network traffic channels. Indeed, special protocols have been developed for IOS and other management type software. These protocols typically assume that each internetwork entity has a network layer address such as an Internet Protocol (IP) address assigned to it. Unfortunately, such internetwork devices typically control or include multiple elements such as line units and trunk units which are ideally individually controllable from the management level perspective of the entire network.
It would, therefore, be advantageous to physically separate network level addresses for the external network management interface from the addresses used for communication among the internal elements within an internetwork device itself.
Furthermore, the internetwork device should be able to automatically configure itself as much as possible, requiring as little customer intervention as possible. Therefore, from the customer""s perspective, an internetwork device should appear to require only a single network address; however, there should be from an internal perspective more than one available address, to efficiently route management level messages internally, and to prevent a possibly catastrophic failure of the device should a management level message be improperly routed.
Furthermore, the provisions for addressing should be such that the internetwork device may be arranged in a redundant configuration as easily as possible, again without complicating the customer""s configuration requirements.
Any such solution for assigning addresses should also be simple and inexpensive as possible since many internetwork devices such as routers, do not contain sophisticated computing equipment such as personal computers, but rather contain only simple controller-like processors.
The present invention is a technique for implementing an addressing scheme within an internetwork device in which internal or other locally controlled elements such as line units and trunk units may be assigned individual addresses. The internetwork device contains a subnetwork interconnecting the internal elements such as via an Ethernet. The internetwork device also includes a second network port that is typically interfaced to a customer management network. The device automatically provides a network address such as an Internet Protocol (IP) address for the management interface, as well as addresses for the internal elements which do not conflict with one another.
In particular, a network manager provisions an address for the internetwork device on the management network as in a manner which is typically the same as assigning addresses for any network device. Once the management network address is assigned, a controller within the internetwork device assigns a subnet address for the internal backplane network which does not conflict with the subnet address of the assigned management address.
In order for the internal port interface devices, such as the trunk cards and line cards, to discover their own address, a controller within the internetwork device sends a broadcast packet message that advertises its own internal subnet address. Each internal port interface device then listens for such broadcast messages and configure its own address accordingly. The port interface devices may then attempt to initiate management protocol commands, such as IOS type commands, over the management interface.
The invention has several advantages. In particular, the customer does not need to configure the system controller""s backplane management addresses. Rather, the customer only needs assign the internetwork device a single subnet address within the context of the customer""s own management network.
The technique also supports a mode whereby the internal port interface devices may correctly react to a redundant controller fail over condition. In the redundant configuration, the internal port interface devices detect the fail over condition of the controller and can rendevous with a current controller in charge. This approach avoids difficulties with prior art static assignment of addresses to line cards and other schemes whereby a manager must provision an address for each individual entity within the internetwork device.